I got you :)
The molecular clock (based on the molecular clock hypothesis (MCH)) is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation. The molecular data used for such calculations is usually nucleotide sequences for DNA or amino acid sequences for proteins. It is sometimes called a gene clock or evolutionary clock.
        
             
        
        
        
The mantle being made of nickel and iron is the correct statement about the geosphere and  is denoted as option B.
<h3>What is Geosphere?</h3>
This is referred to the solid part of the earth and consists of rocky materials present in it.
The geosphere has the mantle which is made up of materials such as iron and nickel which are metals and are responsible for their rigid solid structure thereby ,making it the most appropriate choice.
Read more about Geosphere here brainly.com/question/842883
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Answer:
The correct answer will be option-B.
Explanation:
Photosystem of a plant is complex pigment-protein molecules which absorbs the light energy required for the formation of a glucose molecule.
Two types of Photosystem are present in the plants which are: P₆₈₀ and P₇₀₀. The 680 and 700 denote the wavelength of the light energy absorbed by the pigment of the chloroplast. The electrons get excited only at their absorbing wavelength.
Thus, Option-B is the correct answer.
 
        
             
        
        
        
<span>the record of descent of an animal, showing it to be purebred.</span>
        
                    
             
        
        
        
Answer:
it's either A or D I believe. it's most likely D